ABS Print Temperature and Speed

[KW-Jacky 1]

Dear Sir,

 

It is first time to print ABS on my UM2 EXT. I have installed Front Door and Top Cover to keep the ambient/enclosure temperature.

 

Overall print out is acceptable , but the upper part of the print out is deformed .  I have to enable the part-cooling /  lower the nozzle temperature / speed down the print speed  to fix the problem?

 

Nozzle : 215°C

Bed : 100°C

Layer : 0.2mm

Enclosure temperature : ~40°C

Slicer Cura : Latest Version

Print Speed : 60mm/s

Cooling : OFF 

 

 

 

Regards,

Jacky

 

 

[gr5 2,167]

GOOD START!  40C air temp is perfect.  Don't go much hotter or you risk damaging your servos.  40C should be fine though.  Excellent temp for ABS (by the way I recommend you pick a different material than ABS but that's another subject).

 

215C is much too cold.  240C is more reasonable.

 

What is your fan speed?  Did you turn the fan off?  If so then that's the problem.  That small tower needs extra cooling.  Normally I recommend around 1/4 power so I listen to the noise the fan makes at 100% and keep lowering it until it sounds much quieter.  25% is NOT necessarily 1/4 power.  Make sure the fan actually spins.  Sometimes you set the fan to say 20% and the fan doesn't spin at all.  Typically it takes a little extra to get it spinning and then it will go down to say 10% but if it stops for a second you need to go back up to 30% or something to get it going again.

 

You want to pick a speed where it will start even if you stop the fans with your fingers and let go.

 

Anyway, whatever your fan speed is I suspect it's too slow.

 

[gr5 2,167]

That tower - because it's so small - might need extra cooling (100% fan) or even print a second tower just to the side of the print so the tower layers have a few more seconds to cool before the next layer is placed on top.

[KW-Jacky 1]

Dear gr5,

 

Many referene material mentioned , part cooling is not required for the ABS. Hence I have disabled the part-cooling for this print.  there is no part cooling from Start to End. 

 

I will try enable part cooling (30%) from the layer of this tower start.  

 

Many Thanks 🙂

 

[gr5 2,167]

Let us know what you learn!

[geert_2 557]

I would print a dummy "cooling tower" next to the real model. So the hot nozzle is moved away from the model, while it is busy printing the dummy, and the model has time to cool down and solidify. Where the bottom of the dummy is empty, since the real model is big enough, and the top of the dummy is 100% filled for the extra cooling time.

 

My standard pictures on the subject:

 

Printing with and without dummy:

 

Concept: inverse shaped dummy, to keep printing time per layer constant:

 

Part of a real model, with pink dummy. The dummy is only needed when printing the tiny top area, so the rest is empty:

 

Another real model, with dummy (red). Here too, the dummy is empty, except for the top where it is needed:

 

 

[KW-Jacky 1]

The problem has been fixed by enabled part cooling (regular 40% , maximum 60%). 

 

I will keep it in my memory, the hot plastic needs  cooling time to solidify, the tiny object needs extra cooling time. 

 

I will try print with dummy tower to compare the dirrerene . 

[geert_2 557]

Yes, just do tests on tiny items, so you know from which point on the dummies become necessary. This takes only a few minutes due to their small size, but it can later save a big model. After some time you know and you can add the dummies from the beginning in the design.

 

Below is a real application: the dummy is the green cube at the top right. Its bottom is hollow, its top is filled from the height onwards where the large flat areas in the blue object ends, and only the tiny high yellow part remains. Without dummy cube, the top of the yellow part would seriously deform. For reference: text caps height is 3.5mm, text legs are 0.5mm, thus all is quite small.

 

 

[gr5 2,167]

40% fan seems high for ABS but all fans are different.  Normally you want the minimum fan where it rotates.  Which on some fans is 25% and on other's it's 1% and can be anywhere from 1% to 40%.